MARCH Meeting 2017

Branch President, Mike Green, presented an illustrated talk on kangaroos in their garden, continuing a theme of focussing this year’s DRB talks on natural history in the Hills area.

Kangaroos are herbivores that are native to Australia and its neighbouring islands. They are marsupial mammals of the family Macropodidae (lit. large footed) and classified by size. The family encompasses the kangaroos, wallabies, Tree-kangaroos, Pademelons, Quokkas and others. The Western Grey (Macropus fuliginosus), occasionally a visitor to local gardens, is one of the largest kangaroo species and is found widespread throughout southern, South and Western Australia and as far north as Shark Bay and eastwards into the Goldfields.  The Western Grey Kangaroo possesses a hairy muzzle (rhinarium) and its coat (pelage) has a small range of colour variation from pale grey to brown, with white and lighter colour undersides.

Over a number of years, the Greens have worked to reintroduce Australian native species of trees and shrubs onto their large wooded property. The property also has the benefit of a stream and granite and dolerite outcrops. Because of this, the property also supports and provides a haven for a number of native animals and birds. The talk covered some of the experiences of sharing this large garden with visitations by a mob of Western Grey Kangaroos.

Kangaroos generally feed at the end of the day and through night time, and this brings certain dangers with them establishing in suburbia, notably traffic and fences.  Mike emphasised the importance of constructing boundary fencing making the highest strand clearly visible and marked by a soft white tape. It was noted that the visiting kangaroos are amenable to following trails and once these are established as familiar routes, the rest of the garden is less likely to become common ground. Although the Western Grey Kangaroos feed principally on grasses, leafy shrubs and low trees, the choices of feedstuffs on offer in domestic gardens expands their diet. In establishing a garden, unless young plants are protected by metal mesh enclosures, many species will be sampled as food and destroyed. Flimsy materials, such as plastic, used to enclose plants are easily wrecked, but once plants have reached a couple of years of maturity they are likely to continue to thrive without protective enclosures.

Whilst kangaroos sample roses and Anigozanthos sp., a number of native species are ignored including species of Eremophila, Hypocalymma and Melaleuca. As cellulose, a fibrous material that is the principal food stuff of their diets and is fairly indigestible, their digestive systems have evolved, like sheep, as “foregut fermenters” and they do not “chew cud”. Microorganisms within their enlarged linear stomachs ferment the cellulose, extracting nutriment. They have a comparatively short large colon resulting in less capacity to retain faeces. Kangaroos are very efficient with water intake and can survive a 20 per cent drop in hydration. In hot weather they can sweat and do pant and can be seen to wet their forearms and shins with saliva to remain comfortable.

Kangaroos hop, an unusual mode of locomotion but one common to many Australian mammals. It is energy efficient, compared with some quadrupeds, particularly at speeds of about 20kph. As speed increases so does stride length and they can attain 45kph as short bursts. The Red Kangaroo has been recorded to attain speeds of 70kph.

Young kangaroos are sexually mature at about 2.5 years but need to be about 7 years to grow and mature before breeding. Mike showed that a young kangaroo (joey) attempting to re-enter its mothers pouch is neither a straightforward or elegant act. A fairly large joey will also still feed from its mother’s teats once independent of the pouch and reach into the pouch to do this.

Apart from rare and saddening accidents, life in the suburbs for this family of Western Greys seemed fairly comfortable with the garden providing some of their needs and their habits generally tolerated. Although they are often parasitised by certain tick species, notably Amblyomma triguttatum, known as the Kangaroo Tick, these didn’t seem to bring or result in any illnesses.

As the urban sprawl of Perth continues to obliterate the fragmented small areas of remnant bushland, so the effects on native fauna and flora become an important issue to natural history groups. As residents, we can at best offer safe haven to any opportunistic animals that are left to share our suburbs.

Susan Stocklmayer